Axle drive transmission



Feb. 16, 1937. G. w. HARPER ET AL 2,071,165

AXLE DRIVE TRANSMISSION 7 Filed Dec. 6, 1932 2 Sheets-Sheet 1 I T0 ENGINE VACUUM Y i A:

IN VEN TOR. Geoiye W Harper A/bert R. Catta. BY E g 1 Feb. 16, 1937. a. w. HARPER ET AL AXLE DRIVE TRANSMISSION Filed Dec. 6, 1932 2 Sheets-Sheet 2 INVENTOR Georye W/farper BY A/berl R Caho.

fa A ORNEY.

Patented Feb; 16, 1937 UNITED STATES PATENT OFFICE 2.01135 4 AXLE naive 'rnaivsms'slon George W; Harper and Albert a. we, Cleveland, Ohio, assignors to The OolumbiaAxle Com-- pany, Cleveland, Ohio, a corporation of Ohio Application December'6, ia'szfs m No. 645,968

18 Claims.

This invention relates to multi-speed power transmission mechanisms for automotive vehicles for transmitting power fromthe engine to a driving axle at selective speeds.

When the speed ratio of the power transmittin mechanism between the engine and axle of an.

' 'chronizing the relatively rotating parts upon se- 3 lectively changing from one speed ratio to an-- automotive vehicle is changed while the vehicle is in motion, the line of power transmission is that is to say, synchronized, to avoid the shock.

and strainand deterioration of the mechanical 20 parts whichv would be caused by suddenly over- 'coming the inertia of these parts when their speed is suddenly changed by being again connected to the rear axle.

When the change of speed is made at the conventional transmission gear set immediately adjacent to the engine, the parts whose speed must be changed in the gear set areof relatively light weight and small negligible inertia; and the difference between the speed of these and the other axle-driven partsand the\speed of the engine may be absorbed smoothly and without shock by skillful manipulation of the main driving clutch by the driver. v

' Even in this case, unskillffil operation of the clutch in coordination with adjustment of engine speed will, upon engaging the clutch after" the selective speed change has been made, send a shock through the entire car and power plant as is well known.

' Now, in'the case of transmissions having speed change mechanism disposed relativelyremote from the engine, for example in the driving axle itself, the manipulation of the main driving clutch is inefiective to prevent the above-mentive speed ratios, an improved means for synother.

Another object is to provide for driving axle 5 constructions, a power transmitting mechanism having selective speed ratios and improved means for synchronizing the relatively rotating parts upo'n selectively changing from one speed ratio to another. a p Another object is to provide a power transmission mechanism of the class referred to in which the synchronization is effected through the agency of an .improvedfriction generating or braking device.

Another object is to provide a power transmit ting mechanism of the class referred to having improved synchronizing means and in which the power transmission is eifected through a dual ratio planetary gearing. P

Another object is to provide a power trans- 2o mitting mechanism of the class referred to having selective speed ratios and synchronizing meansand adapted in an improved manner to be operated by engine vacuum.

' Another object is to provide,'in a power trans- 25 mitting mechanism having selective speed ratios and means for synchronizing the relatively rotating parts upon selectively changing fron1\.one

speed ratio to another, an improved means for so introducing a time interval during the change nfrom one s eed to the other.

Another object is to provide, in 'a power transmission mechanism having selective speed ratios and means for synchronizing the relatively moving parts upon selectively changing from one speed ratio to another, an improved means for introducing a predetermined time interval between the change from one speed ratio to the other in' order that synchronization of the parts may be effected in an improved manner.

, Another object is to provide, in a power transmission mechanism having means for providing a time interval as above stated, an improved means for adjustably varying the time interval.

Other objects will be apparent to those skilled-- in the art to which ourinvention appertains,

Our invention is fully disclosed in the following description taken in connection-with the accompanying drawings, and in which:

Fig. 1 is .a sectional view taken on a substantialy horizontal plane through a rear axle power transmitting driving mechanism of the dual ratio planetary type and with an embodiment of my invention applied thereto;

Fig. 4 is a view of a part of Fig. 3 illustrating.

the parts in another position;

Fig. 5 is a view of a part of the mechanism of Fig. 1 but taken from the opposite side thereof; or the view Fig. 5 may be considered as taken approximately from the plane 5 of Fig. 2;

Fig. 6 is a view of a clutch element which we may employ, shown separately, and which is illustrated in Figs. 1 to 4 inclusive associated with other elements;

Fig. 7 is a fragmentary view of a control device which I may employ.

Referring to the drawings, we have shown generally at a main housing comprising aligned oppositely extending generally tubular portions 2 and 3 in which upon suitable roller bearings 4 and 5 the transmission mechanism to be described is rotatably supported; and comprising a forwardly extending tubular portion 6 in which upon suitable roller bearings I and 8 a pinion shaft 9 is rotatably mounted and terminating forwardly and outwardly of the tubular portion 6 in a coupling means 9 adapted to be coupled to the propeller shaft extending rearwardly from the engine, and terminating inwardly of the housing in a bevel pinion l; and the housing comprises a central portion generally housing the pinion l0 and associated transmission elements; and rearwardly, the housing is open but is provided with a cover plate |2 to complete the housing and effect a complete enclosure for the parts of the mechanism.

The pinion l0 meshes with a ring gear I3 rigidly connected to and supported upon a rotatable housing l4 preferably formed from two generally cup-form portions l and I6 joined together and to the ring gear by a circular series of bolts The housing portions l5 and I5 have, respectively, coaxially outwardly extending tubular portions 8 and I9 by which the rotatable housing I4 is rotatably supported in the above-mentioned bearings 4 and 5.

The rotatable housing portion l6 has a portion disposed transversely of its rotational axis and is provided with a corresponding transversely disposed partitionelement 2| inwardly axially spaced from the portion 20; and connecting the portions 20 and 2| is a plurality, such as five (only 7 one of which is shown), of gear shafts 22 disposed parallel to the rotational axis and radially spaced.

gear with the tubular portion l9 of the hous- I ing I4 whereupon, when power from the engine is transmitted through the shaft 9, pinion I II and ring gear l3 to rotate the housing l4, the planet gears 23 will move bodily with the housing and not rotate upon theirshafts 22, and thus the orbit gear 24 will move bodily or in unison with the housing l4 and through the agency of the differential mechanism to be described will rotate the axle shafts 21 and 28 to propel the car at one speed. And, as will become more readily apparent, means is also provided to optionally or selectively connect the sun gear 25 with the stationary housing; whereupon, as the ring gear l3 and housing l4 are rotated, the planet gears 23 will revolve around the sun gear and thus move their orbit gear at a speed greater than that of the *housing I4 and drive the axle shafts 21 and 28 at another and higher speed.

The movement of the orbit gear 24 is'transmitted to the axle shaft as above referred to in the following manner. The teeth of the orbit gear are carried on a spider 30 having oppositely axially extending tubular portions 3| and 32 rotatably mounted in corresponding bearing bores in the tubular portion I8 and in the partition element 2|. A pair of differential bevel gears 33-33 are splined upon splines 34-34 of the axle shafts and have their teeth meshed with a pair of differential pinions 35-35 rotatably mounted upon a pinion shaft 36 extending centrally through the spider 30 and secured therein by apin 31, and the bevel gears 33-33 are rotatably supported by their hubs in the tubular portions 3| and 32.

The transmission mechanism, as thus far described, is generally similar to that forming the subject matter of the patent issued to A. A. Wiedmaier, No. 1,815,689, July 21, 1931, and in view of the more complete description of construction and operation in that patent, it is believed that the foregoing brief description will suffice.

In the transmission mechanism of that patent, and with respect to which the present invention is in some respects an improvement, the optional or selective positive connection of the sun gear 25 with the rotatable housing l4 or with a portion of the stationary housing to change the transmission from one ratio to the other is effected directly and abruptly.

Mechanism forming part of our invention embodiment will now be described whereby this selective connection is first made through a synchronizing clutch mechanism to synchronize the would otherwise be transmitted to the mechanism and to the vehicle by the sudden change of .positive transmission ratio between the axle shafts 21 and 28 and the shaft 9.

The sun gear 25 is elongated axially in the direction away from the teeth engaged with the pinion 23 and is provided with external splines 38-38 integral therewith (see Fig. 3).

The tubular portion l9 of the housing I4 is provided with external splines 39-39. A shiftable clutch element 40, shown separately in Fig. 6 and in cross-section in Fig. 3, is provided, consisting of two parts 4| and. 42, which are axially movable relative to each other. The parts of the clutch are mutually .engageable by annular rows of confronting clutch teeth 43 and 44, respectively, adapted to be meshed upon axial movement toward 'each other and unmeshed'by axial movement in the other direction.

The clutch part 42 is splined upon the splines 38 of the sun gear 25. The clutch part 4| is provided with an external set of clutch teeth 45 and an internal set of clutch teeth 46, the teeth 46 being adapted to be meshed with the splines 39 (see Fig. 3) upon axial movement of the clutch part 4| inwardly or toward the right as viewed in'l 'ig. 3 and to be disengaged fronrthesplines 30 by movement in the other direction. .The clutch teeth 45 are adapted to be engaged with an annular row of clutch teeth 41 provided on the tubular. portion 3 of the stationary housing, (see v 43 into which project, respectively, trimnions 55 I and II of a clutch shifting mechanism to be described later. 5 At this point of the description it is believed suflicient to say that the trunnion: 5l--53 and the trunnions 5|-5| maybe moved toward the left or the right. as viewed in Figl 3 to move the clutch parts 4| and site engage and disengage the teeth 44 and 43;, 45 and 41, and the teeth 45 i and splines 39, and the sequence of these movements will presently be described.

The clutch part 4| has a cylindrical body porotion 52 between the clutch piece 45 and 43 thereof and which is provided with internal axially disposed splines 53. A pair of head plates 54 and 55 have peripheral teeth or splines engaged with i the splines 53 and the plates 55 and 54 are centrally perforated and rotatably mounted upon the splined sun gear 25.

Between the head plates 54 and 55, is a pinrality or pile'of brake discs preferably alternatively of brass and steel or like diiferent materials, and shown generally at 53. The discs of brass are peripherally splined or toothed to engage the splines 53, and are centrally perforated to have rotational relation to the sun gear 35; and the alternate steel discs are of slightly smaller diameter peripherally to clear the splines 53 and are centrally perforated and splined to engage the splines 33 of the sun gear 25. A compression spring 51 is disposed to exert axial thrust upon. the head plate 55 from which it is transmitted through the pile of discs 53 to,

create friction therebetween, and thence to the head plate 54. engage an annular shoulder on the clutch part 40 as at l 3.

V, '1 'he'spring 51 at itsouter end reacts upon the 9 bottoin'ofa cup-form cage 53, the bottom of which is perforated to clear a 'hub,portien, 3 of the clutch part 42 and which hunt-(partition is splined on the splines 33, and the open end of the cup is outwardly flanged as at 4| and lodged be- 55 hind a shoulder 33 on the body. portion oi.- the clutch part 4|. v V

By this construction. willbc observed, the clutch part may be moved to the right or toward the left .as viewed in mg. a and carry with I it its hi-ere plates" autism-me l'l maintaining the plates underfcompression; and during such axial shifting movement, the steel plates may slide in the splines'33. r

The operation of the device as thusfar described will be. explained and then will follow a description of the operating mechanism by which the trunnions 55' and 5| are moved to-eflect the said operation.

70 With the parts in the position-illustratedin Fig. 8, the sun gear is locked to the hub portion l3 and the transmission is at the low speed'ratiig; the said locking engagement being traceable in. I

3 from the sun gear 23', splines 33. clutch 75 art. 42,'engaged teeth 44, 43, clutch part 4|', and

The head plate 54 is formed to viewed in Fig. 3 but with the trunnion 5| movins faster than the trunnion 30. The trunnion will move the clutch part 4| toward the left and cause the tooth 45 to begin to leave the ends of 10 the splines 39. By the time the teeth are ham way out of the splines 39, the teeth have been completely disengaged from the teeth 43 by the more rapid movement of the trunnion 5| axially 1 moving'the clutch part 42. The clutch part 4| 1 continues to move and will presently engage the teeth 41. Y Assuming, of course, that the vehicle is'nioving forwardly, the axle shafts (see Fig. 1) TI-and 28 will be rotating even if power supply from the 20 engine is discontinued, and the axles, acting through the differential spider 30, orbit gear 24 and pinions 23, will rotate the sun gear 25. Beforewthe teeth 44 and 43 were disengaged as above" described, the sun gear rotated the clutch part 25 4| by means of the clutch part 43 and thus the tubular portion l9 wasrotated in unison with the sun gear 25. Upon disengagement of; the teeth 44 and 43., as above described, the clutch part 4| will cont nue to be rotated by the sun gear 25 through the friction of the discs 55.

to rotate by slipping the discs with a braking action so that they are gradually and without transmitting shock to the mechanism brought to rest. As the trunnion -50 continues. to moveto fully engage the teeth 45 and 41, the trunnion 5| moves 45 7 back toward the right and ultimately engages the teeth 44-43 which are now substantially without relative movement. From this time on, the sun gear may be considered as locked to the stationary frame through the spline 38. clutch part 43, 50 teeth 44--43, clutch part and teeth 45, 41.

The parts are now in the position illustrated in Fig. 4 and at the higher speed ratio.

- To shift back to the'lower speed ratio, the

process is just reversed, that is to say, the trun- 55 nioniil starts to move toward the right and the trunnionll moves towards the left; the'teeth 44-43 are first disengaged; the teeth 4'! and 45 are then disengaged; the teeth. 45 engage the splines 39 at a time when the tubular portion i9 is rapidly rotating; the clutch part 4| is suddenly set into motion but shock is prevented by slipping of the plates 55; the driving action of the plates gradually brings the sun gear up to the velocity of the rotating clutch part 4| and then as the teeth 45 move intofull engagement with the splin 39, the trunnion 5| moves toward the right and engages the teeth 44-43 so that the connection between the sun gear 35 and tubular p rtion l9 will not continue to be through the 7 0 siippabie discs but through the positivelock of the teeth 44-43 and spline 33.

Thus-in shifting from either the ,low speed to the high speed or vice versa, the change of mechanical connections is first made momentarily 76 or temporarily through a slipping brake connection to synchronize the speed of the relatively moving parts, and this is presently supplemented by a positive connection for the purposes hereinbefore set forth.

To move the trunnions 58 and 5| with the sequence of movement above described, the following mechanism is provided.

A pair of brackets 18 and 1| are rigidly secured as by bolts 12-42 to the stationary housing and provided with aligned bores 14-14 in which are oscillatably mounted oppositely extending trunnions 13 and 15 formed at the open ends of a generally U-shaped yoke 16.

The trunnion 15 has keyed thereto as at I1 a lever 18 provided with a pair of spaced fingers 19 and 88 and terminating in an eye provided with a bearing pin 8|. A link 82 having forks 83 and 84 at its opposite ends is connected by the fork 83 to the pin 8| and by the fork 84 to a bearing pin 85 on the rearward end of a piston rod 86 reciprocable in a.bearing guim: 81 formed integral with or rigidly connected to the main housing 'I.

As iliustated in Fig. 1, the piston rod 86 is connected to a piston 88 reciprocable in a cylinder 89. A conduit I81 is provided to apply intake suction of the automotive engine to the cylinder 69 on one side of the piston 88 and a similar conduit I88 to apply suction to the cylinder on the other side of the piston whereby the piston may be caused to exert, optionally, thrust on the piston rod 86 forwardly or rearwardly; and the piston rod movement is communicated to the tunnion 15 to oscillate the yoke 16'.

The yoke 1.6 has portions extending beyond each of the trunnions 13 and 15, indicated at 90 and 9|, to which pins 92-92 are rigidly secured having on their inner confronting ends the trunnions 5858 above described, and thus the motion above described for the trunnion 58 will be given thereto by the oscillatory movement of the up'on which are formed the trunnions 5I-5| above described.

The pins 99 are preferably provided with relatively rotatable roller elements I 88-I88 disposed to be engaged by the cam element 94.

The hangers 91 are provided with pins I8 I 8 I .and tension springs |82I82 connect the pins I8| with the pins 92; and thusthe roller elements I 88 are always maintained in pressure contact with the cams 94.

By reference to Figs. 1 and 5, it will now be apparent that when the yoke 16 isoscillated in one direction, that is to say, from the position illustrated, the pins 92 carrying the tunnions 58--58 will be moved correspondingly and the cam projection 96 will move in behind the roller element I88 and move it and the pin 99 outwardly in the same general direction as the pin 92 is moving but with a more rapid movement and that upon continued oscillation of the yoke 16, the pin 92 will continue to move in the same direction but the roller I 88 will roll down from the projection 96, and the projection 96 will be projected under the roller permitting the pin 99 to have a retracted movement toward the pin 92; and thus the above described necessary movement of the trunnions 58 and 6| will be accomplished.

On the return oscillatory movement of the yoke 16, the pin 92 will first have a movement away from the pin 99 and the pin 99 a movement away from the pin 92 as the roller I88 rolls over the projection 96 in the other direction, followed by amovement of the pin 99 toward the pin 92, thus accomplishing the reversed suitable movement of the trunnions 58 and 5| above described.

To insure that the trunnions 58 and 5|, after their clutch shifting movement has been accom plished, will not drag or frictionally engage the sides of their grooves 48 and 49, the movement of the yoke 16 in either direction is predetermined and stopped with thetrunnions 58 and 5| centrally of their grooves by the fingers 19 and 88 moving in unison with the yoke 16 into engagetary valve element I2I having a three-way or T- form duct I22 therein. The valve element I2| has a communication with the atmosphere through a port I23. It is believed that in the well developed state of this art, this brief description and showing will be understood to those skilled in this art in connection with the following mode of operation.

As illustrated, vacuum is supplied by the conduit I88, to the lower side of the piston, and the upper side of the piston communicates with the atmosphere through the duct H8 and the port I23.

By rotating the valve element I2| clockwise as viewed in Fig. 1 through 98, communicating with the atmosphere through the port I23 will be effected by way of the conduit I88 with the cylinder on the lower side of the piston, and the upper side of the piston will communicate with the vacuum/ and in through the conduit I 81, duct I I8, duct-I22 and duct I 28. I

A control device illustrated in Fig. 7, for operating the valve element I 2| and having low and high" indicia to indicate low speed and high speed may be provided comprising an operating handle therefor, I24 and adapted to be mounted upon a panel I 25 of the car or vehicle.

Obviously, the rate-at which the parts of the speed change device above described are moved from one position to the other by the stroke of the piston 88, will be determined by the rate of flow of air into the cylinder 89 on one side or the other of the piston 88 as the case may be.

This rate of flow may normally be determined by the size of the conduits I81 and I88 or other portions of the path of flow, but in order to render the same adjustable, a screw I26 may be provided in the valve device 5 which, by screwing it inwardly or outwardly may decrease or increase the efiective size of the duct I28 to adjust the rate of flow through the conduit system, and thus adjust the length of the time interval of movement of the parts from the position which they occupy at one speed to that which they occupy at another speed. v

Advantages of the above described mechanism and its mode of operation may be stated in another way, as follows:

When the vehicle is in motion, the housing "-16 rotates together with its associated parts including the planetgears 23, ring gear and pinion ill and other parts forward thereof (that is, forwardly in the case of rear axle drive); and the housing 30 is also rotating together with its associated parts including the orbit gear 24, differential gears and axles. When the planetary gearing is in the low. speed ratio, these two housingsare rotating at the same speedaand are connectedby the engaged orbit gear and planetary gear. When the shifter change is made to the higher speed, the housings are first disconnected and the housing 30 goes on rotating at .the same speed, being now driven by the axles; and the housing il-IG must first be slowed down to synchronize it with the housing 30 before the two can be drivingly connected together at the higher speed ratio; this slowing down actionJs efifected through the friction brake as described; when the change is made back to the low speed ratio. the housing Il-IS (and associated parts) must be 'speeded up to synchronize it with the axle-driven that the teeth 44 return to engagement with the teeth 43. These teeth are therefore made with flat confronting faces H and I ll, respectively, whereby they may slide over each otheruntil' the desired synchronism has been effected. It. will be observed that the springs R4192; will; yield as may be ngcessary to resiliently constrain the two clutch parts 4| and 42 toward each. other until their teeth 43+ engage. 5,1{5

In the foregoing we have describedan embodiment of our invention as applied to the rear axle of an automotive vehicle of the more usual or popular construction. Butour invention is not limited to this applicationthereof and may be applied to a front axle or to both axles. r

Our invention is'not limited to the exact details of construction shown and described. Many changes and modifications thereof may be made within the scope and spirit of our invention without sacrificing its advantages.

We claim:---- 1. In a power transmission mechanism for antomotive vehicles to transmit engine power to a vehicle driving axle, a pair of axle elements, differential gearing connecting the axle elements, a first gear for driving the axle elements through V the diiferential gearing, and a second gearfor receiving power from the engine, multi-speedratio transmission gearing between the first and second gears, comprising a planet gear associated scribed in claim 1 and in which the synchroniz- 1 ing mechanism comprises a pair of frictionally engaged brake elements one of which is associated with the sun gear and the other of which is optionally associatable' with the second gear or stationary portion of the vehicle 'tomotive vehicles to transmit engine power to a vehicle driving axle, a pair of driving axle elements, differential gearing connecting the axle elements, a first gear for driving the axle elenients through the' differential gearing, and a second gear for receiving power from the engine, multi-speed-ratio transmission gearing between the first and second gears comprising a planet gear associated with the second gear and meshed with the first gear, and a sun gear meshed with theplanet gear, speed ratio change mechanism comprising a first clutch element having. a frictional engagement with the sun gear and adapted to be shifted to optionally connect with a stationary portion of the vehicle or with the second gear, a second clutch" element rigidly rotatably connected to the sun gear and adapted to be rigidly connected with and disconnected fromthe first clutch element.

5. In a. power transmitting mechanism for automotive. vehicles to transmit engine power to a vehicle driving axle, a pair of driving axle elements, differential gearing connecting the axle elements, a first gear for driving the axle elements through the differential gearing, and a second gear for receiving power from the engine, multi-speed-ratio transmission gearing between the first and second gears comprising ,a

rflsm comprising a first clutch element having'a frictional engagement with the sun gear and 7 adapted to be shifted to optionally connect .with

a stationary portion of the vehicle or with the second gear, a second clutch element rigidly rotatably connected to the sun gear and movable, into rigid connection with the first clutch element orout of connection thergyith, and actuable means for successively disconnecting the '5 clutch elements, shifting the first clutch element and connecting the clutch elements.

claim 5 and in which the actuable means comprises a pair of oscillatable' elements, having each a sliding connection with one of the clutch elements respectively, a cam on one oscillatoryv of the said one oscillatory element in either di-' rection, the other oscillatory element is caused first to move relatively away from the said one oscillatory element and subsequently toward it.

'7. A transmission mechanism as described in 'claimj and in which the actuable means com-' prises a pair of oscillatable elements, having. each a'sliding connection with one of the clutch.

elements respectively, a cam .on one oscillatory element engasing ajcam follower on the other,

whereby oscillatory movement of one of the os- .55 1 '6. A transmission mechanism as describedin,

cillatory elements will oscillate the other, and the cam being so formed that upon movement of the said one oscillatory element in either direction, the other oscillatory element is caused first to move relatively away from the said one oscillatory element and subsequently toward it, and means for moving the said one oscillatory element comprisinga piston and cylinder device connected thereto and actuatable by engine vactruth in the cylinder to communicate oscillatory movement thereto.

8. In a power transmission mechanism for automotive vehicles adapted to transmit engine power to the vehicle driving axles, multi-speed ratio transmission gearing comprising a rotary element connected to the axles to transmit power thereto, and a rotary element connected to the engine and to the first named element to receive power from the engine to transmit it to the axles through the first named element at a selected speed ratio of transmission, mechanism to change the speed ratio of transmission of the two elements from one transmitting speed to another 'speed, mechanism for automatically causing a predetermined time interval to elapse during the change which includes a reciprocatory piston and cylinder device alternatively and optionally operable by application of engine vacuum thereto, and said mechanism also producing a synchronizing effect upon the speed of the rotary engine and axle connected element for a fixed fractional portion of the time interval.

9. In a power transmission for automotive vehicles to transmit engine power to a vehicle driving axle, multi-speed ratio transmission gearing comprising a rotary element connecting the axle to transmit power thereto, a rotary element connected to the engine and to the first named element to receive power from the engine and transmit it to the axle and to the firstnamed element at a selected speed ratio of transmission, mechanism to change the speed ratio of transmission of the two elements from one transmitting speed to another speed, mechanism for automatically causing a predetermined time interval to elapse during the change which mechanism includes a piston cylinder device, means for optionally applying engine vacuum to one side of the piston and atmospheric pressure to the other side, means for adjusting the rate of fiow of air from the atmosphere to adjust the rate of movement of the piston, said mechanism also producing a synchronizing eifect upon the speeds of the rotary engine and axle connected elements for a fixed fractional portion of the time interval.

10. In a power transmission mechanism for automotive vehicles to transmit engine power to a vehicle driving axle, multi-speed-ratio transmission gearing comprising a rotary element con nected to the axle to transmit power thereto,'and a rotary element connected to the engine and to the first named element to receive power from the engine and transmit it to the axle through the first named element at a selected speed ratio of transmission, mechanism to change the speed ratio of transmission of the elements from one transmitting speed to another speed, and mechanism for automatically causing a predetermined time interval to elapse during the change, said mechanism including a walled chamber havin a movable wall connected to the change speed mechanism, means for optionally connecting the chamber on one side of the wall with the engine vacuum and the chamber on the other side of the wall with atmospheric pressure to" effect movement of the movable wall, and a connection be- ,tween the movable wall and the speed change a vehicle driving axle, multi-speed-ratio transmis sion comprising a rotary element connected to the axle to transmit power thereto, and a rotary element connecting the engine to the first named element receiving power from the engine and transmit it to the axle and to the first named element at a selected speed ratio of transmission, mechanism to change the speed ratio of transmission of the two elements from one transmitting speed to another speed, and mechanism for automatically causing a predetermined time interval to elapse during the change, said mechanismincluding an engine vacuum operated device having a movable wall element connected to the speed change mechanism, and said mechanism also producing a synchronizing effect upon the speed of the rotary engine and axle connected elements for a fixed fractional portion of the time interval. I

12. In a power transmitting mechanism forautomotive vehicles to transmit engine power to a vehicle driving axle, a first gear for driving the axle, and a second gear for receiving power from the engine, multi-speed-ratio transmission gearing between the first and second gears comprising a planet gear associated with the second gear and meshed with the first gear, and a sun gear meshed with the planet gear, speed ratio change mechanism comprising a first clutch element having a frictional engagement with the sun gear and adapted to be shifted to optionally connect with a stationary portion of the vehicle or with the 'second gear, a second clutch element rigidly r0- tatably connected to the sun gear and adapted to be rigidly connected with and disconnected from the first clutch element.

13. In a power transmitting mechanism for automotive vehicles to transmit engine power to a vehicle driving axle, a first gear for driving the axle, a second gear for receiving power from the engine, multi-speed-r::-,tio transmission gearing between the first and second gears comprising a planet gear, and a sun gear and orbit gear meshed therewith, speed ratio change mechanism comprisingafirst clutch elementhaving africtional engagement with the sun gear and adapted to be shifted to optionally connect with a stationary portion of the vehicle or to cause the orbit gear, sun gear, and second gear to rotate in unison, a second clutch element rigidly rotatably connected to the sun gear and adapted to be rigidly connected with and disconnected from the first clutch element.

14. In a power transmitting mechanism for automotive vehicles to transmit engine power to a vehicle driving axle, a first gear for driving the axle, and a second gear for receiving power from the engine, multi-speed-ratio transmission gearing between the first and second gears comprising a planet gear associated with the second gear and meshed with the first gear, and a sun gear meshed with the planet gear, speed ratio change mechanism comprising a first clutch element having a frictional engagement with the sun gear and adapted to be shifted to optionally connect with a stationary portion of the vehicle; or with the second gear, a second clutch element-rigidly rotatably connected to the sun gear and movable into rigid connection with'the first clutch element or out of connection therewith, and actuable means for successively disconnecting the clutch elements, shifting the first clutch element and connecting the clutch elements.

15. In a power transmitting mechanism for automative vehicles to transmit engine power to a ving axle, a first gear for driving the axle, atscond gear for receiving power-from the engine, multi-speed-ratio transmission gearing between the first and second gears comprising a i'or successively disconnecting the clutch elements,

shifting the first clutch element and connecting the clutch elements.

16. In a power transmission mechanism for automotive vehicles to transmit engine power to a vehicle driving axle, an axle element, difierential gearing connecting the axle element, a first gear for driving the axle element through the difierential gearing, and a second gear for receiving power from the engine, multi-speed-ratio transmission gearing between the first and second gears, comprising a planet gear associated with the second gear and meshed with the first gear and a sun gear meshed with the planet gear, speed change means comprising means to optionally connect the sun gear to a stationary housing portion of the vehicle or to the second gear, synchronizing means to gradually synchronize the speed of the second gear with the first gear during the changing of speed ratio, and means for actuating the speed change means by power of the vehicle engine.

17.311 a power transmitting mechanism for automotive vehicles to transmit engine power to a vehicle driving axle, a pair driving axle elements, difierential gearing connecting the axle elements, a first gear for driving the axle ele-- ments through the difierential gearing, and a second gear for receiving power from the engine, multi-speed-ratio transmission gearing between the first and second gears comprising a planet gear associated with the second gear and meshed with the first gear, a sun gear meshed with'the planet gear, speed ratio change mechanism comprising the first clutch element having frictional engagement with the sun gear and adapted to be shifted to optionally connect with a stationary portion of the vehicle or with the second gear, a second clutch element rigidly rotatablynconnected to the sun gear and adapted to be rigidly connected with and disconnected from the first clutch element, and means operable by the engine for effecting relative movement of the clutch element.

18. In a power transmitting mechanism for automotive vehicles to transmit engine power to a vehicle driving axle,a first gear for driving the axle, and a second gear ilor receiving power from the engine, multi-speed-ratio transmission gearing between the first and second gears comprising a planet gear associated with the second gear and meshed with the first gear, and a sun gear meshed with the planet gear, speed ratio change mechanism comprising a first clutch element having frictional engagement with the sun gear and adapted to be shitted to optionally connect with a stationary portion oi' the vehicle or with the second gear, a second clutch element rigidly rotatably connected to the sun gear and adapted tobe rigidly connected with and disconnected from the first clu tch element, and manually controllable means operable by the vehicle engine for efiecting engagement and disengage-' 

